We have no evidence as yet about mind or the power to think; it seems to be a widely different kind of soul, differing as what is eternal from what is perishable; it alone is capable of existence in isolation from all other psychic powers.
AristotleThe activity of happiness must occupy an entire lifetime; for one swallow does not a summer make.
AristotleBut what is happiness? If we consider what the function of man is, we find that happiness is a virtuous activity of the soul.
Aristotle